熱封時間(jian)主(zhu)要由制袋機的速度決定(ding)。
速(su)度(du)(du)快，熱(re)(re)封(feng)(feng)(feng)(feng)時(shi)(shi)(shi)(shi)間就短；速(su)度(du)(du)慢，熱(re)(re)封(feng)(feng)(feng)(feng)時(shi)(shi)(shi)(shi)間就長(chang)。熱(re)(re)封(feng)(feng)(feng)(feng)時(shi)(shi)(shi)(shi)間也是影響焊縫(feng)(feng)封(feng)(feng)(feng)(feng)合(he)強度(du)(du)和外(wai)觀(guan)的(de)一(yi)個關鍵(jian)因素(su)。相同的(de)熱(re)(re)封(feng)(feng)(feng)(feng)溫(wen)度(du)(du)和壓力下(xia)，熱(re)(re)封(feng)(feng)(feng)(feng)時(shi)(shi)(shi)(shi)間長(chang)，則熱(re)(re)封(feng)(feng)(feng)(feng)層熔合(he)更(geng)充分，結合(he)更(geng)牢固；但熱(re)(re)封(feng)(feng)(feng)(feng)時(shi)(shi)(shi)(shi)間太長(chang)，容易造成焊縫(feng)(feng)起(qi)皺變(bian)形(xing)，影響平(ping)(ping)整度(du)(du)和外(wai)觀(guan)。熱(re)(re)封(feng)(feng)(feng)(feng)后(hou)的(de)焊縫(feng)(feng)若冷卻(que)(que)不(bu)好，不(bu)但會影響焊疑的(de)外(wai)觀(guan)平(ping)(ping)整度(du)(du)，而且對熱(re)(re)封(feng)(feng)(feng)(feng)強度(du)(du)有一(yi)定的(de)影響，冷卻(que)(que)過(guo)程(cheng)就是通過(guo)在一(yi)定的(de)壓力下(xia)，用較(jiao)低(di)的(de)溫(wen)度(du)(du)對剛(gang)熔融熱(re)(re)封(feng)(feng)(feng)(feng)后(hou)的(de)焊縫(feng)(feng)進行定形(xing)。因此(ci)，壓力不(bu)夠(gou)，冷卻(que)(que)和循(xun)環不(bu)暢(chang)，循(xun)環量不(bu)夠(gou)，水溫(wen)太高(gao)或冷卻(que)(que)不(bu)及時(shi)(shi)(shi)(shi)，都會致使冷卻(que)(que)不(bu)良，熱(re)(re)封(feng)(feng)(feng)(feng)強度(du)(du)降低(di)。